Steam generator



United States Patent [72] inventor James H. Lawler 2003 N. Santa Fe Ave., Compton, California 90221 [21] Appl. No. 830,992 [22] Filed June 6, 1969 [45] Patented Dec. 1, 1970 [5 4] STEAM GENERATOR 13 Claims, 12 Drawing Figs.

[52] US. Cl 122/235 [5 1] Int. Cl. F22b 19/00 [50] Field of Search 122/235,

[56] References Cited UNITED STATES PATENTS 3,382,848 5/1968 Northcote et al 122/235 3,386,420 6/1968 Cleaver et al 122/235 Primary Examiner- Kenneth W. Sprague Attorney-Owen, Wickersham and Erickson ABSTRACT: A steam generator, having in a housing with end plates a series of tubular heat-exchange members fitting snugly against each other and against said end-plates. The heat-exchange members are shaped in groups to provide a series of chambers, so that the flame and the combustion gases from said flame pass serially through a lower chamber, a first transfer chamber, an upper chamber, a second transfer chamber, and a final heating and exhaust chamber, to an exhaust means. In the final heating and exhaust chamber is a steam collection manifold having inlets at intervals on each side midway between its top and bottom surfaces connected to outlet portions of each said heat-exchange member. Inside the manifold is a small-diameter steam outlet tube having a series of small vertical inlets providing restricted openings from the manifold into the 'steam outlet tubes, out of line with the manifold's inlets.

WATER LEVEL Sheet 1 of5 WATER LEVEL FlG 2 INVENTOR. JAMES H. LAWLER flM, u/M

ATTORNEYS Patented Dec. 1, 1970 3,543,732

Sheet Z of 5 JAMES H. LAWLER 00w, MM ATTORNEYS FIG 3 Patented Dec. 1, 1970 3,543,732

60 1;. F 8 INVENTOR.

. JAMES "H. LAWLER F G 7 BY 0mg, av-(1 I ATTORNEYS Patented Dec. 1, 1970 Sheet 5 of5 R a M8 om Y Tw a E mA N W m E i A M M A V J M 2 m 1 5 F 9 @o A LH R 9 ME 9 JG/4'6 V N m m Am 7mm R E EG M U T TN U B SN \SE E 5 G P E J G 9 O W 3 0 6 EC M 2 m H Ra w W EAM C ST ACT 4 L WT 9 m 0 S D t STEAM ps'nsnsron This invention relates to an improved steam generator.

The steam generator of the present invention is characterized by its economical and efficient generation of highpressure somewhat superheated dry steam. The steam so generated has many uses; for example, it may be used to drive steam engines, both stationary and as prime movers for vehicles.

One important use of the invention is in pumping and hottom-hole heating equipment for oil wells. Bottom-hole heating represents a great potential for increased production and secondary recovery in situations where heavy crudes result in production problems. Often, heavy crudcs have caused oil wells to fall below economic returns. Production problems have also arisen with paraffins, asphalts, wax, and some lighter gravity crudes, and these problems, too, can be solved by use of bottom-hole heating.

in prior art systems for bottom-hole heating, hot water has been circulated from conventional low-pressure steam boilers, but these were relatively inefficient because they resulted in relatively low temperatures at the point of contact with the oil sand at the bottom of the well. This prior art method has had some merit at shallow depths, but it has been expensive to operate and has been limited in its application, particularly when lower depths were involved. Electrical heating has been tried extensively and hasbee'n found to be useful to a limited extent in some situations, but not economically practicable, for again, the cost of operation has been high, and in this instance there have been secondary problems of cable maintenance, so that this prior art method also has not proven fully satisfactory.

The steam generator of the present invention may be used in bottom-hole heating to supply high-pressure, high-temperature steam as the source of heat, at the point of contact with the oil economy and at marked increase in the recovery from the wells.

However, the invention is not limited to use in oil well equipment. Another use for it which has been successfully tried on an experimental basis is in supplying power for antomotive vehicles, such as trucks, in a system where gas or burner oil can be burned efficiently and used to power a steam engine with significant reduction in smog production, as compared with internal combustion engines. The steam generator of this invention is characterized by simplicity of construction, making it .readily adaptable to quantity manufacture, while at the same time the steam generator possesses great versatility and effectiveness. lt enables very efficient use of the flame from a burner to heat water and produce steam, and it enables the production of dry highpressure steam. The unit is also well adapted to replacement of individual parts without having to replace the whole unit.

in the invention, a series of tubular heat exchangers, formed into various configurations, is' used not only as the heatexchanger tubes for the water but also as baffles or guides for the passage of the burner flame and heated combustion gas, so that the flame and combustion gas go through a three-path system. No other baffles arerequired, though end walls are provided. The individual heat-exchange members are readily replaceable on an individual basis, so that if one should burn out, it can be quickly replaced; and they are used in parallel rather than in series, so that malfunction or bad operation in one of them does not affect the remaining ones. 7

Another important feature of the invention is that all of these heat-exchanger tubes lead into a central collecting unit, which preferably comprises a cylindrical manifold pipe having inlet openings bored on opposite sides along its path, the openings on one side being staggered relative to on the opposite side. Within this large manifold is provided a smaller outlet steam pipe which is supported at both end walls and extends out through one end wall. This outlet is imperforate except for a series of top and bottom openings, which extend vertically, whereas the inlets into the manifold from the heatexchange tubes extend horizontally. As a result, there is no direct passage from any-of the inlet openings of the manifold into the inlet openings of the outlet pipe. Moreover, the openings into the outlet pipe are smaller in diameter and fewer in number than those into the manifold, being carefully calculated and spaced to provide even intake and at the same time to build up pressure within the manifold, thereby helping to accomplish the desired superheating of the steam and resulting in production of the dry steam.

Other objectsand advantages of the invention will appear from the following description of a preferred embodiment.

in the drawings:

FIG. 1 is a view in side elevation of a steam generator embodying the principles o'fthis invention.

F IG. 2 is a view in section taken along the line 2-2 in FIG. 1.

PEG. 3 is an enlarged view in section of the heat-exchange and steam collection unit, taken along the line 3-3 in FIG.

FIG. 4 is a fragmentary view in perspective of part of a partially assembled unit of FIG. 3, with two of the heat-exchangers being installed or removed and with one end of each of the steam manifold and the water manifold shown in section.

FIG. 5 is a view in end elevation of one of the four types of heat-exchanger units used in the assembly of FIG. 3 with some portions broken'away and shown in section.

FIG. 6 is a view similar to H6. 5 of a second type of heatexchange unit.

FIG. '7 is another similar view of a third type of heat heatexchange unit. I

FIG. 8 is another similar view of the fourth type of heatexchange unit. 1

FIG. 9 is a view in section on a larger scale of the steam collecting manifold, taken along the line 9-9 in FIG. 10.

FIG. it) is a view in section on a reduced scale taken along the line 10-10 in FIG. 9.

FIG. 11 is'a view in section on a reduced scale taken along the line 11-11 in FIG. 9.

FIG. 12 is a diagrammatic view of a bottom-hole heating and pumping system for an oil well, employing-the present connection.

A steam generator 20 of this invention (See FIGS. 1-3) includes a suitable main housing 21 with a bottom wall 22, a top wall 23, side walls 24 and 25, and first and second end plates 26 and 27. The steam generator 20 also includes a suitable burner unit 30 having a supply line 31 for fuel, which may be either oil or gas, a burner nozzle 32 and a combustion air supply line 33 preferably provided with a fan 34 leading into the burner unit 30 to provide a suitable quantity of high-pressure air. The combustion takes place in the steam generator itself 20, which is made up of a series of tubular heat-exchange members described below and formed into various shapes and fitted snugly to provide a bottom chamber 35 for the flame, a first transfer chamber 36 leading to an upper chamber 37, reversing the direction of flow of the hot gases and sends them back toward the opposite end of the unit; there they pass via a second transfer chamber 38 to a final heating and exhaust chamber 39, again reversing the direction of flow. A steam manifold as lies in this chamber 39. The combustion gases are exhausted through an opening ll by an exhaust fan 42 to aid in maintaining a good flow.

Various burners may be used and the particular burner is not necessarily critical. The fan 34 for the supply of combustion air and the exhaust fan 42 may be any of many units that are readily purchased so long as the ample flow and pressure are maintained.

The series of heat-exchanger members are unusual and vary in structure somewhat from each other. In the preferred form of the invention, the heat-exchanger assembly 50 compresses four types of heat-exchange members 51, 52, 53, 54, each made from metal tubing, typically one-inch tubing. Each of them has a bottom horizontal portion 55 connected at each end to vertical portions 56 and 57, the portion 56 having a steam outlet portion 53 leading into the manifold lt preferably without welding by a suitable tube fitting 58a such as a double nippcr with a center keyed head, such as that shown in U.S. Pat. Nos. 2,934,362 and 3,290,069. Each member 51, 52, 53, 54- also has a water-inlet portion 59 connected to a water supply manifold 60, preferably by the same head of fitting 58a as that used with the manifold 40, so that each tube can be installed and removed without welding or cutting.

The heat-exchange member 51 (FIG. 8) comprises a generally rectangular formation with the upper end of the vertical portion 57 connected to the vertical portion 56 by an upper-height horizontal portion 61. This upper-height horizontal portion is also present in the heat-exchange mem bers 53 and 5d. The heat-exchanger member 52 has a medium-height horizontal portion 6 2 connecting the vertical portions 56 and 57. This portion 62 is also present in the heatexchange members 53 and 5d. The vertical member 56 in the member 52 alone extends up to a closed end 63 well above the portion 62. The members 53 and 5 thus have both of the portion til and 62, they differ from each other in that, in addition, the member 54 has a plurality 'of spaced-apart vertical tubes 64 connecting the portions 61 and 62. 7

When the four devices just described are used in conjunction with each other, it becomes possible to make patterns such as the one shown in MG. 3 to achieve the chambers 35, 36 37, 38 and 39. Thus, the member 52 may provide the first 7 tubes at the inlet end followed by 25 members 53 and 54 together in a group, followed in turn by the last seven tubes, all members 51. The first member 52 rests snugly against the end plate 26, and the last member 51 rests snugly against the end plate 27. All the heat-exchange members 51, 52, 53, 54 rest snugly against each other, to enclose the chambers 35, 36, 37, and 38 between them, with the aid of the end plates; the chamber 39 is provided above the members 51, 53, and 54 with the aid of the top-wall 23 and the upper portions of the side walls 24 and 25.

in the center grouping, most of the heat-exchange members are of the type 53, but about one in four is preferably of the type 54 with the vertical tubes at. This grouping gives more efficient heating of the water in the assembly as a whole, without overimpeding the flow of the combustion gas.

As shown in FIG. 4 the assembly 50 is made 5 made without welding the members 51, 52, 53, 54 together, and those members are individually replaceable. By detaching their outlet 58 from the manifold 40 and their inlet 59 from the manifold 60, the member 51, 52; 53 or 54 is easily taken out and a new one inserted.

' The structure of the members 51, 52, 53 and 54 and their assembly along the lines described produce the path 35, 36, 3'7, 38, and 39 for passage of the flame and combustion gases which heat the members'5ll, 52, 53, 54, and it will'be noted that in the pass 39, the outlet ends 5% are heated as is the manifold 40. Also, although there are only four types of the heat-exchange members, they are alternated in their attitude so that their outlet 58 is first on one side and then on the other side of the manifold 40 and, the inlets 59 are similarly first on one side of the manifold 60 and, the inlets 59 are similarly first on one side of the manifold 65 and then on the other side. Accordingly, the manifold d0 is provided with staggered inlet openings 68, and the manifold 60 provided with staggered inlets 69'.

The steam manifold d0 (FIGS ll especially) may comprise a solid walled tube bored to provide the inlet openings 68, which extend horizontally in on each side; the manifold 40 has no other such openings. One end 70 is closed by a solid closure member or plate 71 that is provided with a tubular interior socket '72.. The other end '73 is closed by a plate or closure member 74 having an outlet opening '75. A smaller steam outlet pipe 80 fits inside the manifold 40, having one end Sll closed by the supporting socket 72 within which it tits, and the other open end 52. extending out through the outlet opening 75. This pipe 80 is bored vertically to provide openings ti? and 84 along both top and bottom, they being staggered relative to each other. into these openings 53 and and into them only passes all the steam output from the steam generator of this in vention. l prefer to have ten of these openings $25, as, one eighth inch in diameter each, in a ii -inch pipe Ed. The inlet openings on are typically one-eighth inch in diameter in a pipe 4% that is three or four inches in diameter, and there are many more of the openings 68 than there are the openings 83 and 84. For example, there may be thirty openings pouring steam into the manifold 4t) and all of that leaving through about ten openings d3, 34 so located that there is never any direct access from the openings 68 to the openings S3, 34; this means that-in view of the heating of the manifold sit by the combustion gases in the chamber 39the steam in the manifold 40 is superheated, and dry superheated steam issues from the outlet tube 50.

Condensate which collects falls down in the vertical tubes 56, 57 and is reused or withdrawn through the manifold es. The condensate is usually sent back toward the bottom of these heat exchangers; it is still warm and therefore takes less heat in being reheated. This, therefore, increases the efticiency of operation. The water level is kept about as shown in H6. 2 to obtain high efficiency. The upper portions only of the heat-exchange members 511, 52, 53, 5d are thus above water level and provide the steam.

When using this invention in a bottom-hole heating unit for oil wells (See FIG. 12), the high pressure steam is flowed from the steam generator 20 to the bottom of the oil well through a suitable valve 90, a pipe 91 and an oil well casing 92 and is returned in the form of condensate by the casing 92 and a pipe 93 to a water storage tank 94. A typical steam generator 2t? of this invention is typically capable of supplying 600 pounds per hour of 600 psi. steam at 675 F. The unit 20 can furnish 300 p.s.i. steam within ten minutes after being fired up, and yet the gas consumption in the burner 30 is lower than that of conventional units which have been used in bottom-hole heating, the gas consumption of this device being about 300 cubic feet per hour. in many instances the gas for the burner 30 can be supplied by the well with casing 92 but a pipe 95. The steam for the generator 20 can also be used to operate a steam engine as that drives a pumping jack 97 with condensate being collected and recirculated for it likewise. The water system involves a closed system in the oil well operations, with condensation returning to the bank 9 to the steam generator 20, so that no fresh supply ofwater is really essential except to replace a small amount of condensation that evaporates from the supply makeup tank. The condensation in the return line acts as a seal to retain the temperature at the bottom heat exchanger 98 automatically. The oil withdrawn from the casing 92 by the pumping jack 9'7 goes to oil storage tanks 99 and l that are steam heated by heating coils 101.

in a test with this device, a submarginal producing well was chosen. The well before installation of this invention had a daily average production of 2.5 barrels. After introducing the system of thisinvention, production increased to 9 barrels per day, or an increase of 6.5 barrels, 300 percent. At the same time, the gas consumed in this unit was only 100 cubic feet per hour, and such gas is often available from field sources right at the well. The particular well tested was 2,200 feet deep, a typical depth for wells in the field where that well was located. In this particular device the operating pressure was kept at between 150 to 500 p.s.i., and the steam temperature into the heat-exchange system was 250 to 400, the condensate returned from the heat-exchange system being between F. and l80 F. The specific gravity of the oil was 12 AH, and the actual tests and the oil temperature at the well bottom when in use with this invention was to 250 F.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

l claim:

l. A steam generator, includingin combination:

main housing having top, bottom, and side walls, and first and second end plates at opposite ends;

a series of tubular heat-exchange members in said housing,

fitting snugly against each other and at the ends of the series, against a said end plates;

each said heat-exchange member having a horizontal bottom tubular portion and first and second vertically extending tubular portions communicating interiorly with opposite ends of said bottom portion, a steam outlet portion leading from each said first vertically extending portion, and a water inlet portion leading into each said bottom portion;

a first group of said heat-exchange members lying adjacent said second end plate, each having an upper-height horizontal portion interiorly and exteriorly connecting said two vertical portions;

a second group of said heat-exchange members adjacent said first-end plate, each having a medium-height horizontal portion interiorly and exteriorly connecting said vertical portions;

a third group comprising the remaining said heat-exchange members and lying between said first and second groups, each said heat-exchange member in said third group having both medium-height and upper-height horizontal portions interiorly and exteriorly connecting the two vertical portions;

whereby said second and third groups define a lower chamber bounded by their said bottom, vertical, and mediumheight portions, said third group defines an upper chamber bounded by said medium-height, vertical, and upper-height portions, said first group defines a first transfer chamber between said bottom, vertical, and upper-height portions, said first transfer chamber joining said lower and upper chambers, said second group also defining a second transfer chamber leading from said upper chamber into afinal heating and exhaust chamber defined above said upper-height portions of said first and third groups and the top and side walls of said main housmg;

exhaust means leading out from said exhaust ca chamber through said second end plate;

steam collection and delivery means in said final heating and exhaust chamber having inlets connected to said out let portions of said heat-exchange members;

a water supply manifold in the bottom of said housing below the bottom portions of said heat-exchange members and connected to said inlet portions of said heat-exchange members; and

fuel-burning means in said lower chamber, so that the flame and combustion gases from said flame pass serially through said lower chamber, said first transfer chamber, said upper chamber, said second transfer chamber, and said final heatingand exhaust chamber to said exhaust meansv 2. The steam generator of claim 1 wherein said steam collection and delivery means comprises:

a steam collection manifold comprising a large-diameter tube in said exhaust chamber and extending horizontally between said end plates, having one and blocked by a first closure member and the other end blocked by a second closure member having an opening therethrough, said manifold having its said inlets leading horizontally thereinto at intervals on opposite sides of said tube, being the said inlets connected to said outlet portions of each said heat-exchange member; and

a small diameter steam outlet tube inside said manifold supported at each end by said closure members and extending out through said opening in said second closure member, said steam outlet tube having a series or" vertical restricted inlet openings into said steam outlet tubes and. lying approximately at right angles to the inlets into said manifold.

Lil

3. The steam generator of claim 1 wherein some of the heatexchange members in said third group have a series of spaced apart vertical tubes joining said medium-height and upperheight portions and in communication therewith interiorly.

i. A steam generator, including in combination:

a main housing having top, bottom, and side walls, and first and second end plates at opposite ends;

a series of tubular heat-exchange members in said housing, fitting snugly against each other and lying parallel to said end plates, the heat-exchange member at each end fitting snugly against one said end plate, each said heatexchange member having a horizontal bottom tubular portion and first and second vertically extending tubular portions communicating interiorly with opposite ends of said bottom portion, a steam outlet portion leading from each said first vertically extending portion, and a water inlet portion leading into each said bottom portion;

said heat-exchange members being alternated throughout said series so that the outlet portions of the odd-numbered members lie on'the opposite sides of said series from the outlet portions of even-numbered members, the inlet portions also alternating similarly from side to side;

a first group of said heat-exchange members lying adjacent said second end plate, each having an upper-height horizontal portion intcriorly and extcriorly connecting said two vertical portions at the upper end of said second vertical portion;

a second group of said heat-exchange members adjacent said first end plate, each having a mcdium'height horizontal portion interiorly and cxteriorly connecting said vertical portions, both of which extend well above said mcdiurn-height portion, said second vertical portion being blocked at its upper end;

a third group comprising the remaining said heat-exchange members and lying between said first and second groups, each said heat-exchange member in said third group having both medium-height and upper-height horizontal portions interiorly and exteriorly connecting the two vertical portions;

whereby said second and third groups define a lower chamber bounded by their said bottom, vertical, and

medium-height portions, said third group defines an upper chamber bounded by its said medium-height, vertical, and upper-height portions, said first group defines a first transfer chamber between its said bottom, vertical, and upper-height portions, said first transfer chamber joining said lower and upper chambers, said second group also defining a second transfer chamber leading from said upper chamber into a final heating and exhaust chamber defined above said upper-height portions of said first and third groups, between them and the top and side walls of said main housing;

exhaust means leading out from said exhaust chamber through said second end plate;

a steam collection manifold in said final heating and exhaust chamber extending horizontally from one said end plate to the other and comprising a large diameter tube having one end blocked by a first closure member providing an internal support socket and the other end blocked by a second closure member having an outlet tube opening therethrough, said manifold being bored horizontally at intervals on each side midway between its top and bottom surfaces to provide inlets connected to said outlet portions of each said heat cxchange member, the inlets on one side being spaced evenly between the inlets on the other side;

a small-diameter horizontal steam outlet tube inside said manifold, supported at one end by said support socket and extending out through said outlet tube opening at the other end and then out through one of said end plates, said steam outlet tube having a series of small vertical inlet openings through its upper and lower extremities providing restricted openings into said steam outlet tube;

a water supply manifold in the bottom of said housing below the bottom portions ofsaid heat-exchange members and connected to said inlet portions of said heat-exchange members;

fuel-supply means, fuel-igniting means, and combustion air supply means leading through said first end plate into said lower chamber;

fuel-burning means, in said lower chamber; and

so that the flame and combustion gases from said flame pass serially through said lower chamber, said first transfer chamber, said upper chamber, said second transfer chamber, and said exhaust chamber to said exhaust means.

5. The steam generator of claim 4 wherein said air supply means comprises means for supplying air under pressure to said fuel burning means.

6. The steam generator of claim 55 wherein said exhaust means comprises fan means for pulling the combustion gas from said exhaust chamber.

7. The steam generator of claim 3, wherein the inlets to said manifold are more numerous than the inlet openings into said steam outlet tube and have a greater total cross-sectional area, so that steam under pressure builds up in said manifold and said steam outlet tube conducts away dry superheated steam.

3. The steam generator of claim wherein some of the said heat-exchange members in said third group have in addition a series of vertical tubes spaced apart from each other and interiorly and exteriorly connecting said, medium-height and upper-height portions.

9. A steam generator, includingin combination:

a main housing having top, bottom, and side walls, and first and second end plates at opposite ends;

a series of tubular heat-exchange members in said housing, fitting snugly against each other and lying parallel to said end plates, the heat-exchange member at each end fitting snugly against one said end plate;

each said heat-exchange member having a horizontal bottom tubular portion and first and second vertically extending tubular portions communicating interiorly with opposite ends of said bottom portion, a steam outlet portion leading from each said first vertically extending portion, and a water inlet portion leading into each said bottom portion;

said heat-exchange members being alternated throughout said series so that the outlet portions of the odd-numbered members lie onthe opposite sides of said series from the outlet portions of even-numbered members, the inlet portions also alternating similarly from side to side;

a first group of said heat-exchange members lying adjacent said second end plate, each having an upper-height horizontal portion interiorly and exteriorly connecting said two vertical portions at, the upper end of said second vertical portion;

a second group of said heat-exchange members adjacent said first end plate, each having a medium-height horizontal portion interiorly and exteriorly connecting said vertical portions, both of which extend well above said mediurn-height portion, said second vertical portion being blocked at its upper end;

a third group comprising the remaining said heat-exchange membersand lying between said first and second groups, each said heat-exchange member in said third group having both medium-height and upper-height horizontal portions interiorly and exteriorly connecting the two vertical portions;

whereby said second and third groups define a lower chamber bounded by their said bottom, vertical, and medium-height portions, said third group defines an upper chamber between its said medium-height, vertical, and upper-height portionsQsaid first group defines a first transfer chamber between its said bottom, vertical, upper-height portions, said first transfer chamber joining said lower and upper chamber chambers, said second group also defining a second transcr chamber leading from said upper chamber into a final-heating and exhaust chamber defined above said upper-height portions of said first and third groups between them and the top and walls of said main housing;

exhaust means leading out from said exhaust chamber through said second end plate;

steam collection and delivery means in said final-heating and exhaust chamber extending horizontally from one said end plate to the other and having inlets connected to said outlet portions of each said heat-exchange member and having steam delivery means leading out through one of said end plates;

a water supply manifold in the bottom of said housing below the bottom portions of said heat-exchange members and connected to said inlet portions of said heat-exchange members;

fuel supply means fuel-igniting means, and combustion air supply means leading through said first end plate into said lower chamber; and

iuel-burnig burning means in said lower chamber so that the flame and the combustion gases from said flame pass serially through said lower chamber, said first transfer chamber, said upper chamber, said second transfer chamber, and said exhaust chamber to said exhaust means.

ill. The steam generator of claim 8 wherein said air supply means comprises means for supplying air under pressure to said fuel burning means.

ll. The steam generator of claim 9 wherein said exhaust means comprises fan means for pulling the combustion gas from said exhaust chamber.

12. The steam generator of claim 8 wherein some of the said heat-exchange members in said third group have in addition a series of vertical tubes spaced apart from each other and interiorly and exteriorly connecting said medium-height and upper-height portions.

A steam generator including in combination:

a main housing having top, bottom, and side walls, and first and second end plates at opposite ends;

a series of tubular heat-exchange members in said housing, each said heat exchange member having a steam outlet portion at its upper end and a water inlet portion leading into its lower end;

means for heating said heat-exchange members;

a steam collection manifold comprising a large-diameter tube having one end blocked by a first closure member providing an internal support socket and the other end bloclced by a second closure member having an outlet tube opening thcrethrough, said manifold being bored horizontally at intervals on each side midway between its top and bottom surfaces to provide inlets connected to said outlet portions of each said heat-exchange member, the inlets on one side being spaced evenly between the inlets on the other side, said manifold extending horizontally from one said end plate to the other; and

a small-diameter steam outlet tube inside said manifold,

supported at one end by said support socket and extending out through said outlet tube opening at the other end and then out through one of said end plates, said steam outlet tube having a series of small vertical inlet openings through its upper and lower extremities providing restricted openings into said steam outlet tube.

PC4050 UNITED STATES PATENT OFFICE 569 CERTIFICATE OF CORRECTION Patent No. 3,543,732 Dated December L 1970 I d!) James H. Lawler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r Column 1, line 37, after "oil" insert sand, thereby enabling effective heating of wells at a high degree of operating line 69, after "to" insert those Colu: 2, line 27, delete "heat", first occurrence. Column 3, lim 41, after "is made" delete "s made". Column 5, line 5, aft "against" delete "a"; line 42, after "exhaust" delete "ca". Column 7, line 8, delete "and".

Signed and sealed this 8th day of June 1971.

(SEAL) Attest:

EDWARD M.FIETCHER,JR. WILLIAM E. SCHUYLER, Attesting Officer Commissioner of Paten1 

